The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Engine control systems have been developed to control fuel injection based on an air/fuel ratio of an engine. The air/fuel ratio is typically determined based on an oxygen level detected by an oxygen sensor. The oxygen sensor may not detect oxygen levels as accurately as desired when the engine is initially started. Thus, some engine control systems operate in an open-loop mode when an engine is initially started. In the open-loop mode, fuel injection is controlled independent of the oxygen sensor output.
Fuel quality may vary depending on a time of year and a geographic location. In the open-loop mode, variations in fuel quality may cause drivability issues such as engine stalls and vehicle vibrations. Also, additional fuel is required during transient maneuvers such as increasing a throttle position to wide open throttle. Traditional engine control systems do not account for variations in fuel quality when increasing fuel injection amounts during transient maneuvers while operating in the open-loop mode.